A butterfly-type exhaust gas circulation valve that circulates exhaust gas of an engine to an air supply passage is composed of a valve element that opens and closes an exhaust gas passage and a support shaft that causes the valve element to operate, and the support shaft is supported by a bearing (bearing portion) provided in a housing so as to be rotatable about itself. In the exhaust gas circulation valve having the above configuration, displacement and tilting of the support shaft directly lead to leakage of circulated exhaust gas in a state in which the valve element abuts on a valve seat, and hence it is extremely important to hold the bearing at a predetermined position.
A typical exhaust gas circulation valve is constituted by an aluminum housing, and hence there is a problem in that a holding force becomes insufficient when the bearing is press-fit into the aluminum housing and fixed.
To cope with this, Patent Document 1, for example, proposes a method of fixing a rolling bearing in which a bearing is fixed to the housing by using another component. A rolling bearing fixing device according to Patent document 1 has a structure in which an outer ring of the rolling bearing is fixed to a housing by using the following: the housing; the rolling bearing (bearing) in which a plurality of rolling elements are disposed between the outer ring and an inner ring so as to be rollable in a circumferential direction; a pair of annular fixing plates that sandwich the housing in an axial direction therebetween and hold both ends of the outer ring therebetween; and a bolt that couples the pair of fixing plates via the housing in the axial direction.